Magnetic recording materials, more particularly video tapes which record information in short wavelengths, require excellent video electromagnetic properties. Therefore, it is desired to improve surface smoothness of the magnetic layer. On the other hand, improvement in audio electromagnetic properties are also required of the magnetic recording materials, and it is desired to increase the amount of a magnetic powder in the magnetic layer.
Hitherto, carbon black has been incorporated in a magnetic layer of a magnetic recording material mainly for the purpose of preventing the generation of static charges. Carbon black used generally has a mean primary grain size of 10 to 150 m.mu.. In such a case, however, both surface smoothness of the magnetic layer and amount of a magnetic powder to be included in the magnetic layer are not satisfactory at the same time so that a magnetic recording material excellent in both video and audio electromagnetic properties has not been produced.
In addition, incorporation of a mixture of carbon black having a mean primary grain size of 10 to 30 m.mu. with carbon black having a mean primary grain size of 60 to 120 m.mu. was proposed with the intention of increasing the abrasion resistance and preventing a curling phenomenon (Japanese Patent Publication Nos. 9041/79 and 20203/78), but only unsatisfactory results were obtained.